Device for reflecting electromagnetic radiation

Abstract

A reflectarray utilizes switching devices with non-ideal impedance characteristics to vary the impedance of reflecting elements. The antennas of the reflecting elements are configured as a function of the impedance of the non-ideal switching devices to provide optimal phase-amplitude performance. In particular, the antennas are configured such that the impedance of each antenna is proportional to the square root of the impedance of the non-ideal switching devices when in an on state and when in an off state.

1. A device for reflecting electromagnetic radiation, the device comprising:
 an array of reflecting elements, each reflecting element comprising:
 an antenna; and 
 a non-ideal switching device in electrical signal communication with the antenna; 
 
 wherein the antennas are configured as a function of the impedance of the non-ideal switching devices. 
 
   
   
     2. The device of  claim 1  wherein physical attributes of the antennas are configured as a function of the impedance of the non-ideal switching devices. 
   
   
     3. The device of  claim 1  wherein the antennas are configured as a function of the impedance of the non-ideal switching devices when in an on state (Z on ) and when in an off state (Z off ). 
   
   
     4. The device of  claim 1  wherein the antennas are configured to have an impedance (Z antenna ) that is conjugate to the square root of the impedance of the non-ideal switching devices when in an on state (Z on ) multiplied by the impedance of the non-ideal switching devices when in an off state (Z off ). 
   
   
     5. The device of  claim 1  wherein the non-ideal switching devices are solid-state transistors. 
   
   
     6. The device of  claim 1  wherein each antenna has a terminal that is connected to a drain of its corresponding solid-state transistor. 
   
   
     7. The device of  claim 1  wherein the antennas are planar patch antennas that are formed on a substrate and wherein the non-ideal switching devices are individually packaged surface mount solid-state transistors. 
   
   
     8. The device of  claim 1  wherein the non-ideal switching device exhibits non-ideal on and off impedances at radio frequencies above 20 GHz. 
   
   
     9. A device for reflecting electromagnetic radiation, the device comprising:
 an array of reflecting elements, each reflecting element comprising:
 an antenna; and 
 a solid-state transistor in electrical signal communication with the antenna; 
 
 wherein the antennas are configured as a function of impedance characteristics of the solid-state transistors. 
 
   
   
     10. The device of  claim 9  wherein the solid-state transistors exhibit non-ideal on and off impedances at radio frequencies above 20 GHz. 
   
   
     11. The device of  claim 9  wherein physical attributes of the antennas are configured as a function of the impedance of the solid-state transistors when in an on state (Z on ) and when in an off static (Z off ). 
   
   
     12. The device of  claim 9  wherein the antennas are configured to have an impedance (Z antenna ) that is conjugate to the square root of the impedance of the switching devices when in an on state (Z on ) multiplied by the impedance of the switching devices when in an off state (Z off ). 
   
   
     13. The device of  claim 9  wherein each antenna has a terminal that is connected to the drain of its corresponding solid-state transistor. 
   
   
     14. The device of  claim 9  wherein the drains of the solid-state transistors are shorted. 
   
   
     15. The device of  claim 9  wherein the solid-state transistors are individually packaged and surface mounted to a substrate. 
   
   
     16. The device of  claim 9  wherein the antennas are planar patch antennas, each planar patch antenna being electrically connected to the drain of its corresponding solid-slate transistor. 
   
   
     17. The device of  claim 9  wherein the planar patch antennas are formed on an insulating substrate tat includes a pound plane, the pound plane being electrically connected to the source of the solid-state transistors. 
   
   
     18. A device for reflecting electromagnetic radiation, the device comprising:
 an array of reflecting elements, each reflecting element comprising:
 an antenna; and 
 a non-ideal switching device in electrical signal communication with the antenna; 
 
 wherein the antennas are configured to have an impedance (Z antenna ) that is conjugate to the square root of the impedance of the non-ideal switching devices when in an on state (Z on ) multiplied by the impedance of the non-ideal switching devices when in an off state (Z off ) in order to optimize the phase-amplitude performance of the reflecting elements. 
 
   
   
     19. The device of  claim 18  wherein the antennas are planar patch antennas that are formed on a substrate and wherein the non-ideal switching devices are individually packaged surface mount field effect transistors (FETs). 
   
   
     20. The device of  claim 19  wherein the PETs exhibit non-ideal on and off impedances at radio frequencies above 20 GHz.